textproduct: Albany

WHAT HAS CHANGED

Increased QPF amounts from 06 - 12 UTC Monday given high probabilities from the HREF and other guidance for 6hrly rainfall amounts exceeding 0.50" from the Capital District into areas north and west. The highest probabilities remain in the Mohawk Valley and southwest Adirondacks and Upper Hudson Valley where we continue to message the potential for poor drainage flooding tonight into early Monday. Otherwise, no significant changes to the forecast.

KEY MESSAGES

1) There is a low chance for some ponding of water in poor drainage and/or low-lying areas tonight into tomorrow morning, especially for the Capital District, Mohawk Valley, southwest Adirondacks, and Upper Hudson Valley as a period of moderate rain moves through tonight into Monday morning.

2) Temperatures trend warmer Tuesday and Wednesday with a chance for showers and a few thunderstorms for the middle to end of the week.

DISCUSSION

KEY MESSAGE 1... Rain showers that have impacted much of eastern NY and western New England today will continue diminishing in coverage and exiting to our east as a sfc low developing off the coast of NJ lifts northward. With the strongest warm air and moisture advection exiting into New England the rest of the afternoon into this evening, we should enter in a break from the widespread wet weather. However, clouds persist and we cannot rule out patchy drizzle or a few isolated, brief showers as raw and chilly conditions continue. Temperatures will remain well below normal for late May in the upper 40s to low 50s.

As the coastal low tracks northward towards 06 UTC, the sfc warm front will also lift northward and become draped from the Ohio Valley into southern New England. Meanwhile, a rather vigorous shortwave trough positioned near the Hudson Bay amplifies and become negatively tilted. Increased CVA spreading into the Great Lakes/Northeast combined with enhanced divergence in the equatorward entrance region of a jet streak tracking up the Saint Lawrence River Valley will lead to an area of enhanced mid-level FGEN along the front in western NY. Meanwhile, south- southwesterly winds in the 850 - 700hPa layer strengthen, directing a plume of moisture into the Northeast with PWATs reaching 1.5 - 1.6" tonight and IVT anomalies reaching 3 to 4 ST DEV above normal. The region of mid- level FGEN looks to sweep from west to east tonight into early Monday reaching the Mohawk Valley, southwest Adirondacks and Upper Hudson Valley by 06 - 09 UTC before sliding into the rest of eastern NY and western New England by 09 - 15 UTC Monday.

Probabilistic guidance from the HREF remains rather impressive for 6-hourly rainfall amounts late tonight through Monday morning; therefore, our key message for poor drainage flooding potential continues. Latest values show a greater than 75% chance for rainfall amounts from 06 - 12 UTC Monday to exceed 0.50" for the Capital District and areas north and west with even a 30 to 50% chance to exceed 1 inch in the western Mohawk Valley. Weak MUCAPE tonight also suggests the potential for elevated instability through early Monday morning. With warm cloud depths greater than 10kft, efficient warm rain processes can enhance rainfall rates. As the area of moderate rain slides eastward 12 - 15 UTC Monday, 6-hourly rainfall probabilities greater than 0.50" trend downwards (as it outruns the stronger upper level forcing) but remain 40 to 60%. This suggests that while steady rain continues, the potential for poor drainage flooding should trend downwards compared to areas north/west. By 15 - 18 UTC, steady rain finally exits to our east with clouds giving way to breaks of afternoon sun and temperatures warm into the 70s. Thus, the second half of the Memorial Day holiday will feature improved weather conditions for outdoor activities.

KEY MESSAGE 2...Tuesday will likely be the nicest day of the week thanks to zonal aloft and sfc high pressure building overhead leading to seasonably warm temperatures. Then, we will monitor a compact and rather potent shortwave diving southward out of northern Quebec that has potential to cut-off and lead to a closed region of high pressure in the Central Plain. While there are uncertainties regarding timing, position and intensity of the closed low, there is a general consensus for it and its associated cold front to dive southeastward into the Northeast Wednesday or Wednesday night. If the front pushes through our area too early in the day, the higher potential for thunderstorms would shift to our south. Northwest flow dominates the pattern in the Northeast for the second half of the week as an omega block persists in the Central Plains. Additional shortwaves tracking downstream of the omega block will keep low chances for showers in the forecast each day with seasonably cool temperatures.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

Through 18z/Monday...Current KENX radar shows the first batch of light rain showers moving out to the northeast over the next hour or two. Ceilings will generally be MVFR in the 1500 to 2000 ft AGL range throughout the afternoon with periods of IFR ceilings where showers still linger especially at KGFL where 700-900 ft AGL are possible. Visibility will generally be about 6SM this afternoon once this morning's showers wrap up. Hi-res guidance suggest there could be a brief period of slight improvement with a short pause in the rain around sunset this evening however MVFR ceilings still persist due to ample low level moisture. KGFL could see some areas of patchy fog limiting visibilities this evening. Another round of steadier showers will return again late tonight beginning with MVFR flight conditions and very likely lowering to IFR/LIFR visibilities and ceilings between about 05z to 09z at KGFL and 10z to 14z at KALB, KPOU, and KPSF with bursts of heavier rain moving through from west to east. Visibilities should improve to greater than 6 SM by tomorrow afternoon and ceilings begin to trend towards improvement but will likely remain MVFR across all of the terminals through the remainder of the TAF period.

Current winds at KALB, KPSF, and KGFL range from northerly to easterly at 5-10 kt through this afternoon with a few stronger gusts near 15 kt possible. KPOU remains light and variable through this evening. Winds generally become 5 kt or less this evening through the first half of the night before becoming variable 4-6 kt into tomorrow morning and early afternoon.

Outlook...

Monday Night: No Operational Impact. NO SIG WX. Tuesday: No Operational Impact. NO SIG WX. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: Moderate Operational Impact. Chance of SHRA...TSRA. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: No Operational Impact. NO SIG WX. Thursday Night: No Operational Impact. NO SIG WX. Friday: Low Operational Impact. Slight Chance of SHRA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.